1. Field of the Invention
This invention relates in general to obstetric devices, and more particular to devices useful in removing the fetus during vaginal delivery.
2. Prior Art
Today's state of the art obstetrics utilizes various procedures to assist in instances of difficult vaginal deliveries. These procedures basically fall into three categories: version, Caesarian, and device assisted delivery. The devices used in the prior art have two principal subcategories: forceps and vacuum extraction. In the case of severe cephalo-pelvic disproportion, placenta previa, vaso previa, and other contraindications to vaginal delivery, the "C-Section," whether classic or low transverse, remains the mainstay procedure. However, it has long been recognized that to the extent that C-Section deliveries can be successfully avoided, statistical. maternal and fetal benefits will be realized. Even the non-difficult vaginal delivery can benefit from non-traumatic assists.
Many problems may develop during delivery which require assistance from the attending obstetrician to successfully remove the baby from the birth canal. One such problem results from the presenting part of the baby, usually its head, descending too slowly. This is particularly true in the case of the primigravida mother. Even with a completely dilated and effaced cervix, and an adequate pelvis, a fetus might refuse to descend beyond station "+1", especially when the mother is suffering from contraction exhaustion. Slow descent remains a problem even with an assist from administration of oxytocin (Pitocin). The problem of slow descent can also be exacerbated by anesthesia, especially epidural anesthesia, which frequently produces induced non-beneficial partial atony of the engaged and dedicated muscles. Such partial atony frequently results in non-beneficial, and sometimes hazardous, prolongation of labor.
Forceps are limited by the stage of delivery at which they may be safely applied. Station "+1" is considered mid-pelvis and in the usual case is considered too high for a forceps-assisted delivery. The risks to the fetus with forceps application at this level are extreme. Forceps cannot be safely used until the presenting part is at least at station "+2", and preferably between stations "+2" and "+3", which is the floor of the perineum. Modern obstetrics has not developed an alternative to the use of forceps when an assisted natural delivery is indicated, such as when the fetus is consistently exhibiting late decelerations of heartbeat following contractions or is exhibiting non-variability of the baseline heartbeat rate.
Obstetrical forceps are typically, in their various types, two-bladed instruments which are blindly inserted one blade at a time in a hopefully temporal-cheek position and then articulated together before assisting traction is applied. Actual traction is exerted slightly below or underneath the mandible. Traction applied with forceps is point concentrated and slippage of the forceps is increased because of natural lubrication, refusal of the fetal skull to conform to existing forceps design, and other known myriad of variables that vary from one fetus-to-pelvis physical relationship to another.
Even proper positioning of the forceps can result in harm to the fetus. For example, in instances of minimal cephalo-pelvic disproportion, the insertion of one blade of the forceps can exacerbate any slight deficiency in birth canal adequacy. In addition the softness, or pliability, of the fetal skull, coupled with the existence of sutures which separate the plates of the skull, render the skull susceptible to trauma associated with metal forceps assisted deliveries.
In an attempt to alleviate the potential trauma of forceps, vacuum extractors have seen some use. Devices which use cloth or other pliable materials which envelope the fetal head have also been developed. However, because these devices are pliable, insertion of these devices can be problematic or slow. What is needed is a device for assisting childbirth which is safe for the mother and the fetus and which overcomes the shortcomings of the prior art.